It is anticipated that Internet Protocol (IP) traffic will be an important traffic type in future communication transport networks such as networks using Dense Wavelength Division Multiplexing (DWDM).
A wavelength switching optical network (WSON) using dense wavelength division multiplexing (DWDM) may be formed by a plurality of interconnected reconfigurable optical add drop multiplexers (ROADM).
At the interface between an IP network and a wavelength switching optical network (WSON) an IP border node IP router is typically coupled to two wavelength switching optical network WSON border node reconfigurable optical add drop multiplexers (ROADM).
The IP router is provided with transponders/DWDM interfaces, used to form an optical channel carrying an IP traffic channel. The reconfigurable optical add drop multiplexers (ROADM) of the wavelength switching optical network (WSON) are able to route an optical signal through the wavelength switching optical network (WSON) until the optical signal arrives at a wavelength switching optical network WSON border node coupled to a destination IP router.
If a fault within the wavelength switching optical network (WSON) is detected by the IP router, the IP router is able to re-route the traffic channel to the second border node of the wavelength switching optical network (WSON) for transport within the wavelength switching optical network (WSON) to the destination IP router, thus providing fault resiliency for a single fault.
However, if a fault develops on the new optical channel path through the wavelength switching optical network (WSON) the IP router is unable to re-route the traffic channel.
The present invention seeks to provide a novel method and apparatus for optical path validation in an optical network that alleviates or ameliorates at least some of the disadvantages of the prior art.